1. Field of the Invention
The present invention relates to a compressor for an air conditioner or the like, and more particularly to a discharge valve apparatus of a compressor by which a discharge valve element thereof can be easily closed or opened to thereby improve the efficiency of the compressor, and at the same time, to increase reliability of the compressor by way of reduced danger of valve destruction.
2. Description of the Prior Art
Generally, a compressor, as illustrated in FIG. 1, includes a body 1 as an enclosure, a stator 3 disposed within the body 1 to thereby receive electric power from an outside source for the formation of a magnetic field, a rotor 5 for being rotated by the magnetic field, a rotary shaft 9 formed at one end thereof with an eccentric shaft 7 and rotated with the rotor 5, a roller member 11 mounted on the eccentric shaft 7 to perform a rotary motion and a sliding motion, an upper flange 15 fixed at an upper side of a cylinder member 13 and a lower flange 17 fixed at a lower side of the cylinder member 13.
The body 1 is provided at an upper surface thereof with a discharge pipe 19 for guiding a flow of refrigerant compressed in the cylinder member 13, and is also provided at one side thereof with a suction pipe 21 for guiding incoming refrigerant into the cylinder member 13.
The upper flange 15 has a discharge hole 15a interconnected with a discharge port 13a formed at the cylinder member 13 to thereby allow discharge of the refrigerant compressed in the cylinder member 13.
Furthermore, as illustrated in FIGS. 2A and 2B, the upper flange 15 includes a valve plate 23 formed with a discharge hole 23a aligned with the hole 15a for guiding the refrigerant compressed in the cylinder member 13. A valve stopper 27 is spaced at a predetermined height (H) above the plate 23 in order to limit the opening travel of a discharge reed disposed at an upper surface of the valve plate 23. A valve spring 29 is provided between the discharge reed 25 and the valve stopper 27 to flexibly control the discharge reed 25. A discharge valve member 20 (hereinafter referred to as a first discharge valve member) is defined by the discharge reed 25, valve spring 29 and the valve stopper 27 which are fastened to the valve plate 23 by fastening means 31.
The stator 3 creates the magnetic field when energized, and when the rotor 5 is rotated by the magnetic field the rotary shaft 9 joined to the rotor 5 is also rotated.
The eccentric shaft 7 provided on the rotary shaft 9 is rotated with the rotary shaft 9 at a high speed, and the roller member 11 thereon causes refrigerant to be sucked in through the suction pipe 21 and compressed to a high temperature and also high pressure.
When pressure in the cylinder member 13 goes up above a predetermined level, the discharge reed 25 moves to an open state shown in FIG. 3B from the FIG. 3A closed state, until an end portion of the discharge reed 25 collides with the valve stopper 27 as shown in FIG. 3C, and then assumes a bent FIG. 3D state of "S" shape.
When the discharge reed 25 is completely opened, as explained above, to thereby enable the refrigerant to be discharged, the pressure in cylinder member 13 decreases, whereupon the discharge reed 25 is closed in a reverse order of the opening process, to thereby stop the discharge of the refrigerant.
Meanwhile, the oil stored in an oil chamber 33 formed at a bottom of the compressor body is moved up to the rotary shaft 9 by an oil paddle (not shown) disposed within the rotary shaft 9 in response to rotation of the rotary shaft 9, thereby providing cooling and lubricating functions in order to reduce friction between the rotary shaft 9 and the upper and lower flanges 15 and 17, and between the rotary shaft 9, eccentric shaft 7 and the roller member 11. The oil is ejected through a plurality of oil orifices (not shown) formed around the periphery of the rotary shaft 9.
However, there is a problem in the discharge valve member 20 (the first discharge valve member) of the conventional compressor thus constructed, as illustrated in FIGS. 3A to 3D, because when the discharge reed 25 is in an open state, a tip end portion of the discharge reed 25 collides with the valve stopper 27 to generate locally a large amount of collision stress and to thereby possibly damage the apparatus including the discharge reed 25, and at the same time, to increase the closing time because a conversion must be made from the bent "S" state of the shaft to effect a closing operation.
Accordingly, in order to solve the above-mentioned problem, a conventional discharge valve member 30 (hereinafter referred to as a second discharge valve member), as illustrated in FIGS. 4A, 4B, and 5A-5C is coupled with a valve stopper 127 provided with a curved portion 27a to thereby reduce the collision stress of the discharge reed 25.
In other words, when the pressure in the cylinder member 13 reaches a predetermined level, the discharge reed 25 begins to open along the curvature of the valve stopper 127 as illustrated in FIG. 5B until completely opened as shown in FIG. 5C, and when the pressure in the cylinder member 13 goes down, the procedure is reversed to thereby close the discharge reed 25.
However, there is another problem in the second discharge valve member 30 thus constructed, because although the collision stress of the tip end portion of the discharge reed 25 can be greatly reduced, a strong stress is generated around a neck area of a relatively narrow discharge reed 25 because the discharge reed 25 must be bent along the curvature of the valve stopper 27, and it takes a lengthy period of time for the discharge reed 25 to be completely opened, and at the same time, a contact area of oil film is broadened to thereby delay a closing time of the discharge reed 25 because the discharge reed 25 is tightly contacted against the valve stopper 27 along a fairly large area.